In a semiconductor manufacturing apparatus or the like, an integrated valve 1001 is arranged for integration of valves as shown in FIG. 25 for example such that fluid devices 1102 including a pump upstream valve, a liquid stopper valve for cleaning, a pump, a pump downstream valve, a filter, and a valve for air release from the filter are mounted on flow-passage blocks 1101 formed therein with flow passages. When the fluid devices 1102 are mounted to configure such integrated valve 1001, as shown in FIG. 26, a sealing member such an O-ring 1103 is placed in the joining portion of flow passages 1111 and 1112 to prevent liquid leakage. FIG. 27 is an enlarged sectional view showing a sealing part indicated by a broken line D in FIG. 26.
The flow-passage block 1101 and a body 1121 of the fluid device 1102 are formed with the flow passages 1111 and 1112 respectively. In a portion joining both flow passages, a seal holding part 1130 having a space for receiving the O-ring 1103 is formed. This O-ring 1103 is placed between the flow-passage block 1101 and the fluid device 1102 connected thereto. The O-ring 1103 is made of a rubber material and initially has a circular section as shown by a broken line in FIG. 27, but it is deformed by pressing as illustrated, coming into close contact with the flow-passage block 1101 and a body 1121 of the fluid device 1102. Thus, this hermetically seals the flow passage joining portion to prevent the flowing liquid from leaking out.
[Patent Document 1] U.S. Pat. No. 5,505,464, specification